Johns isn't building a team out of characters we know, he's building a team out of heavily modified or completely new characters.

Like, this doesn't so much make JLA #1 not a shitty comic as it makes it obvious that JLA#1 was sort of inevitably going to be a shitty comic. "Supergroup" teams like this (teams made up of already big-deal characters, as opposed to stuff like the Runaways or X-Men where the characters are all basically created within the team context) work because they can use the shorthand you mention, cutting them off from that because you're simultaneously relaunching the team that forms after they're established heroes AND relaunching the heroes themselves in a context you're still establishing elsewhere just doesn't work too good.